Sony PFM-500A3WE Service Manual page 76

3-5. Video Processor Adjustment
YUV Level Check and Adjustment
1. Connect the 525/60 signal to the YUV input connec-
tor.
2. Select the color bar signal.
3. Measure the voltage waveform at pin-14 of IC1003
with an oscilloscope. Confirm that the video signal
excluding sync signal has the following amplitude.
660 mV ± 5 %
(If the video signal excluding sync is outside the
specifications, adjust the video signal level using the Y
GAIN.)
4. Measure the voltage waveform at pin-15 of IC1003
with an oscilloscope. Confirm that the R-Y signal has
the following amplitude.
580 mV ± 5 %
(If the R-Y signal is outside the specifications, adjust
the R-Y signal level using the R-Y GAIN.)
5. Measure the voltage waveform at pin-4 of IC1003 with
an oscilloscope. Confirm that the B-Y signal has the
following amplitude.
700 mV ± 5 %
(If the B-Y signal is outside the specifications, adjust
the B-Y signal level using the B-Y GAIN.)
Cutoff Adjustment
1. Connect the Y signal of the 525/60 signal to the Y
input only of the YUV input connector.
2. Select the gray scale signal.
3. Observe the dark area of display screen. Adjust R
CUTOFF and B CUTOFF until the dark area has
completely no color at all.
3-24
3-6. Watch Error Adjustment
1. Connect the jig circuit as shown in Fig. (b) and a
frequency counter to the B board CN18.
2. Enter the measurement value on a frequency counter in
the WATCH ERROR.
WATCH ERROR Jig Circuit
10k
Frequency counter
Fig. (b)
PFM-500A3WE/500A3WG/500A3WU/510A2WE/510A2WG/510A2WU
CN18
1 VCC
2 CLOCK
3 GND